local shacheng_active = fk.CreateSkill {
  name = "shacheng_active",
}

shacheng_active:addEffect("active", {
  mute = true,
  card_num = 1,
  target_num = 1,
  expand_pile = "shacheng",
  card_filter =function (self, player, to_select, selected)
    return #selected == 0 and player:getPileNameOfId(to_select) == "shacheng"
  end,
  target_filter =function (self, player, to_select, selected, selected_cards, card, extra_data)
    return #selected == 0 and table.contains(player:getMark("shacheng-tmp"), to_select)
  end,
})

return shacheng_active